What you essentially describe is a perpetual motion machine which the law of conservation does not allow for. However, Toyota Prius's use it's braking system to help recharge it's battery. As for how that works, I'm not sure.

What you essentially describe is a perpetual motion machine which the law of conservation does not allow for. However, Toyota Prius's use it's braking system to help recharge it's battery. As for how that works, I'm not sure.

So you couldn't have a vehicle that has been fully charged at your home, and drive around with having the spinning wheels create energy to keep the the battery charged. I may be dumb, but can someone explain to me in a way I could understand why it wouldn't work.

So you couldn't have a vehicle that has been fully charged at your home, and drive around with having the spinning wheels create energy to keep the the battery charged. I may be dumb, but can someone explain to me in a way I could understand why it wouldn't work.

1/. Energy transfer is never fully efficient, there are always losses through atmospheric heating, noise production etc.
2/. By introducing a method of charging into the wheels you increase the load on the wheels, therefore you're just increasing the rate of energy transfer needlessly incurring additional loss though inefficiency.

The alternator. So basically this idea is debunked because it couldn't generate enough energy to keep the car running?

This is actually slightly different. Yes the car does generate energy from the motor running to charge the battery, but it is not energy recuperation, just transfer. The only reason it does this it to charge the battery, it's an inefficient addition of a process in reality.

As previously stated there are research methods into other recuperation methods with a focus on breaking, where the aim is to transfer the energy into say a flywheel instead of just transferring to heat in the break pads. Off the top of my head, doesn't KERS in F1 do this?

I just had a random thought, couldn't they make a self sustaining electric vehicle by using the momentum of the spinning wheels to generate electricity to charge the battery?

You can't take energy from a spinning wheel without slowing that wheel down some. It's why generators have to have an engine running to keep the generator part spinning while it's making electricity.

If you take energy out of the battery, use it to spin the wheels, and then take the energy back out of the wheels and put it back in the battery, you will have slowed the car back down. You will also not get 100% of the energy you put into the wheels back out of them because of losses from the wire and friction etc.

Basically, the only way to gain net energy from a spinning object is to slow that object down.

Electric cars and hybrid cars already do this, it's called regenerative braking. When you hit the brakes it puts energy into the battery by slowing down the wheels/car. When you hit the gas again it puts that energy back into the motion of the wheels and car, but as said above it loses some percentage in both directions.

Trying to keep a car going the same speed with an electric motor at the same time that you try to generate power back from the wheels with a generator will actually slow the car down more than if you just let it coast. You are taking energy from the motion of the car, converting it to electrical energy, converting it back to motion, and putting it back to the same wheels you took it out of, losing energy to heat and friction all the way.

Energy from coasting wouldn't work? I'm just too dumb to understand why something has to be slowed down for this to work lol. Oh well

Because you can't get energy for free. You can't make energy, only move it or convert it to a different form. If you take energy from a spinning wheel, the spinning wheel no longer has as much energy as it used to.

If you've ever used a generator (like gas or diesel powered), if you plug in something that uses a lot of power to it you will actually hear the engine load down and have to work harder. The more energy you try to pull from a generator, the more energy you have to spend to turn it. It doesn't make energy, it just converts it from gasoline, to spinning motion, and then to electricity.

Here's another way to think about it:

A car could go down the road at a fixed speed without using any energy at all if there were no friction in the bearings, no friction of the wheels on the road, and no air resistance to slow the car down. Those things do actually all exist though, so if you shut the engine off while going down the road the car will slow down and eventually stop.

Since a car is therefore always losing energy (it is escaping from the car, mostly as heat, from the bearings, tires, and from air resistance), you have to keep putting energy back into it to keep it going the same speed.

It says the video is private. I will bet though that there is some sort of energy input into the roller coaster at some point. There has to be, because of the friction of the wheels and the friction from the air: http://en.wikipedia....erpetual_motion

Nevermind, it was removed. But it was a old Toyota commercial talking about a self sustaining roller coaster a couple years back.

Maybe they meant 'self sustaining' as in using 'green' renewable energy to power it, like wind or solar.